In ancient Mesopotamia, the facts of nature were attributed to the workings of divine forces. Thus, there were many gods and goddesses, including four creator gods who were themselves created by the forces of Taimat and Abzu, who had emerged from a primordial chaos of water. [See the Greek story of creation out of Chaos.] The highest of the four gods was the sky-god An, the over-arching bowl of heaven. Next came Enlil who could either produce raging storms or act to help man. Nin-khursag was the earth goddess. The fourth god was Enki, the water god and patron of wisdom. These four did not act alone, but consulted with an assembly of fifty, the Annunaki. In addition to these gods and goddesses, the world was populated with innumerable spirits and demons.
The gods bound people together in their social groups and provided what they needed to survive. The Sumerians developed stories and festivals to explain and harness help for their physical environment. Once a year came the new year and with it the Sumerians thought the gods decided what would happen to mankind for the coming year. Otherwise, the gods and goddesses were more concerned with their own feasting, drinking, fighting, and arguing. But they could be prevailed upon to help on occasion if ceremonies were performed to their liking. And so, the priestly class developed.
Source: Chester G. Starr History of the Ancient World
